An oxygen absorber is contained in the packages of food products and drugs as well as cosmetic products, electronic components and the like. The purpose thereof is to prevent oxygen remaining in or gradually permeating into the packages from altering the effective ingredient, flavor or color tone of the respective products to markedly deteriorate their commercial values.
Conventionally, an oxygen absorber comprising iron powder as a main reactant or a substance which is easily oxidized, such as ascorbic acid or gallic acid, is allowed to coexist as an antioxidant in the packages.
Patent Documents 1 to 3 propose a resin composition with an oxygen-absorbing capacity comprising an oxygen-deficient inorganic oxide and a thermoplastic resin, or a laminate for packaging comprising a layer formed from the resin composition with an oxygen-absorbing capacity.
The resin compositions that are concretely disclosed in Patent Documents 1 to 3 contain at most 65 parts by weight of an oxygen-deficient cerium oxide with respect to 100 parts by weight of the thermoplastic resin (39.4% by weight of an oxygen-deficient cerium oxide in the resin composition).
However, Patent Documents 1 to 3 do not concretely disclose a resin composition with an oxygen-absorbing capacity comprising an oxygen-deficient inorganic oxide in an amount of more than 50% by weight or a laminate comprising an oxygen-absorbing layer composed of the resin composition.
With regard to the reason for controlling the content of the oxygen-deficient inorganic oxide in the resin composition with an oxygen-absorbing capacity or the oxygen-absorbing layer to be 50% by weight or less, Patent Documents 2 and 3 disclose that, when the content of oxygen-deficient cerium oxide is higher than 50% by weight, the oxygen-absorbing layer may become fragile and the strength of the laminate for packaging may thus not be maintained.